diff --git a/src/docs/user/userguide/arcanist_commit_ranges.diviner b/src/docs/user/userguide/arcanist_commit_ranges.diviner
--- a/src/docs/user/userguide/arcanist_commit_ranges.diviner
+++ b/src/docs/user/userguide/arcanist_commit_ranges.diviner
@@ -193,12 +193,14 @@
 
 This rule works well for trees that look like this:
 
+```
   |   *  Commit B1, on branch "subfeature" (HEAD)
   |  /
   | *    Commit A1, on branch "feature"
   |/
   *      Commit M1, on branch "master"
   |
+```
 
 This tree represents using feature branches to develop one feature ("feature"),
 and then creating a sub-branch to develop a dependent feature ("subfeature").
@@ -218,6 +220,7 @@
 However, this rule will select the wrong commit range in some cases. For
 instance, it will do the wrong thing in this tree:
 
+```
   |
   | *    Commit A2, on branch "feature" (HEAD)
   | |
@@ -227,6 +230,7 @@
   |/
   *      Commit M1, on branch "master"
   |
+```
 
 This tree represents making another commit (`A2`) on "feature", on top of `A1`.
 
@@ -240,6 +244,7 @@
 
 This rule will also select the wrong commit range in a tree like this:
 
+```
   |
   | *    Commit A1', on branch "feature", created by amending A1
   | |
@@ -249,6 +254,7 @@
   |/
   *      Commit M1, on branch "master"
   |
+```
 
 This tree represents amending `A1` without rebasing "subfeature", so that `A1`
 is no longer on "feature" (replaced with `A1'`) but still on "subfeature". In
@@ -269,6 +275,7 @@
 `.` and the selected base commit. It stops when it encounters a bookmark. For
 example, if you have a tree like this:
 
+```
   |
   | *  C4 (outgoing, bookmark: stripes)
   | |
@@ -278,6 +285,7 @@
   |/
   *    C1 (pushed, no bookmark)
   |
+```
 
 When run from `C4`, this rule will select just `C4`, stopping on `C3` because
 it has a different bookmark. When run from `C3`, it will select `C2` and `C3`.